Stator winding connection arrangement for electric motor

ABSTRACT

There is disclosed an electric motor, which contains a plurality of windings wound around a stator core and a plurality of winding terminal receiving portions for containing that include terminal portions of the plurality of windings in a peripheral direction of the stator core at an interval. In addition, the motor includes a terminal plate with lead wires that are drawn out of the plurality of windings along the peripheral direction of the stator core, and connection fittings for electrically connecting the winding terminals to the corresponding lead wires.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electric motor incorporated in acompressor or the like mounted on an air conditioner or the like, andmore particularly, it relates to an attachment structure of a lead wiredrawn out of a stator winding.

2. Background Art

As shown in FIG. 11, an electric motor 1 a incorporated in a compressor1 mounted on an air conditioner or the like is constituted of a rotor 3fixed to a rotation shaft 2, and a stator 4 disposed on an outerperipheral side of the rotor 3 via a small gap.

A top plan view of the stator 4 is shown in FIG. 12. The stator 4 isconstituted of a stator core 5 having a plurality of (six in thedrawing) magnetic pole teeth disposed in a peripheral direction at apredetermined interval so as to project toward a central portion (therotor), and stator windings 7 a to 7 f wound around the respectivemagnetic pole teeth of the stator core 5 via insulating members 6. In anend surface portion of the stator core 5, a plurality of windingterminal receiving portions 8 a to 8 f are disposed integrally with theinsulating members 6. These winding terminal receiving portions 8 a to 8f are dispersedly disposed on the end surface portion of the stator core5 in the peripheral direction to accept winding ends of the respectivestator windings 7 a to 7 f closely disposed.

The stator windings 7 a to 7 f are connected to a power source via alead wire unit 11. The lead wire unit 11 is constituted of lead wires 13a to 13 f, winding side connection fittings 12 (FIG. 13) electricallyconnected to respective one ends of the wires and attached to thewinding terminal receiving portions 8 a to 8 f, and a power sourceconnector 14 disposed on the other end of the lead wire.

In general, attaching of terminal portions of the respective statorwindings to the winding terminal receiving portions 8 a to 8 f andinserting/fixing of the connection portion 12 can be automated. In theattaching of the lead wire unit 11, however, for example, with athree-phase motor, two for each phase, that is, six winding terminals 9a to 9 f in total are present, and six connection fittings 12 and sixlead wires 13 a to 13 f are therefore necessary. Therefore,manufacturing cost of the lead wire unit 11 is raised, further a largenumber of processes are necessary for attaching the unit, and from thisaspect, cost also increases.

Moreover, for the conventional connection fitting 12, while the leadwires 13 a to 13 f are inserted into lower cutouts of the connectionfittings 12 in a radial direction, the connection fitting 12 is presseddownward to break insulation of the lead wire and electrically connectthe connection fitting 12 to the lead wire. In this case, the lead wires13 a to 13 f turned in the radial directions to be inserted into theconnection fittings 12 are led around in the peripheral direction andconnected to the power source connector 14, and therefore flexing forcesact on the lead wires 13 a to 13 f in the connection fittings 12.Therefore, when an external force is further applied to the lead wires13 a to 13 f and the connection fittings 12, there is a possibility thatdisconnection and connection defect occur with the lead wire.

In order to avoid the aforementioned disadvantage, as shown in FIG. 14,the flexing force is prevented from acting on the lead wire. Windingterminal receiving portions 16 for a three-phase motor are collectivelydisposed in one place on the end surface of the stator core 5, thewinding terminal is attached in a vertical direction to a connectionterminal 15 disposed in the winding terminal receiving portion 16, andfurther a bifurcated terminal conductor 18 a disposed on a terminalplate 17 is pressed from above and inserted into the connection terminal15 to put the winding terminal between leg portions, so that the windingterminal is electrically connected to the terminal conductor 18 a. Theother end of the terminal conductor 18 a whose one end is verticallyinserted into the connection terminal 15 is bent as a terminal conductor18 b at right angles in the terminal plate 17 and extended to theoutside in the radial direction. A casing 19 is formed to surround theterminal conductor 18 b. The terminal conductor 18 b and casing 19 arejoined to a winding end side connection portion 11 a of the lead wireunit 11 to constitute a connection terminal for electric connection.

A connection structure of FIG. 14 can solve a problem of flexing forceexerted on the lead wire in FIGS. 12 and 13, but it is necessary to leada far detached winding terminal along the insulating member 6 to thewinding terminal receiving portion 16. Therefore, a winder structure forperforming this operation becomes complicated. Furthermore, in thiscase, the terminal plate 17 needs to be integrally molded with aterminal 18 by a resin mold, and this is one factor to cause costincrease.

SUMMARY OF THE INVENTION

The present invention has been developed in consideration of theaforementioned circumstances, and an object thereof is to provide ahighly reliable motor in which to attach a lead wire unit to the motor,the number of operation processes can be reduced to achieve costdecrease, and further a damage associated with leading of a lead wiredoes not easily occur.

To achieve the aforementioned object, according to one embodiment of thepresent invention, there is provided a motor comprising a plurality ofwindings wound around a stator core; a plurality of winding terminalreceiving portions, disposed on an end surface portion of the statorcore at an interval in a peripheral direction, for individuallyreceiving a plurality of winding terminal portions; a plurality of firstconductive connection fittings, attached to said respective windingterminal receiving portions, for fixing said winding terminal portionsto said winding terminal receiving portions and for electricallyconnecting with said winding terminal portions; a plurality of secondconductive connection fittings whose one surface side is provided with aprojection for contacting said first connection fitting and whose othersurface side is provided with a lead wire which is electricallyconnected to said winding terminal portion and which extends through thesecond conductive connection fittings in the peripheral direction ofsaid stator core; and a terminal plate having connection fittingreceiving portions to which said plurality of second connection fittingsare attached and which are dispersed in the peripheral direction so asto correspond to said plurality of winding terminal receiving portions.

According to another embodiment, there is provided a motor comprising aplurality of windings wound around a stator core; a plurality of windingterminal receiving portions, disposed on an end surface portion of saidstator core at an interval in a peripheral direction, for individuallyreceiving a plurality of winding terminal portions; a plurality ofconnection fittings which fixes said winding terminal portion to saidwinding terminal receiving portion and which electrically connects withsaid winding terminal portion on one side, said plurality of connectionfittings having a groove through which a lead wire connected to saidwinding terminal portion passes in the peripheral direction of saidstator core on the other side; and a terminal plate having connectionfitting receiving portions to which said plurality of connectionfittings are attached and which are dispersed in the peripheraldirection so as to correspond to said plurality of winding terminalreceiving portions; said connection fitting being beforehand attached toeither of said winding terminal receiving portion and said terminalplate. According to this embodiment, since the number of materials orthe number of components can be reduced, the number of processes andcost can further be reduced.

The winding terminal portion may be drawn in a radial direction of astator and fixed to the first connection fitting. This can prevent aflexing force from acting on the lead wire in a lead wire connectionportion.

The connection fitting may be attached to constitute a pressure contacttype terminal for breaking an insulation coat of the winding or the leadwire disposed beforehand for electrically conductive contact. This cansimplify an assembly operation.

The terminal plate is provided with a guide groove for guiding the leadwire, and this guide groove may have a width substantially equivalent toa diameter of the lead wire, and also have a depth such that a pluralityof lead wires can be superposed and accommodated. This can prevent thelead wires from jumping out or crossing one another when the wires areled around.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a stator according to a first embodiment ofthe present invention,

FIG. 2 is a perspective view showing a first connection fitting in FIG.1,

FIG. 3 is an enlarged perspective view of a winding terminal receivingportion in FIG. 1,

FIG. 4 is a perspective view of a terminal plate to be assembled with astator of FIG. 1,

FIG. 5 is a sectional view of the terminal plate of FIG. 4,

FIG. 6 is a diagram showing that a lead wire unit is attached to theterminal plate of FIG. 4,

FIG. 7 is a perspective view of a second connection fitting to beassembled with the stator of FIG. 1,

FIG. 8 is a diagram showing that the terminal plate of FIG. 5 isattached to the stator of FIG. 1,

FIG. 9 is a perspective view of a connection fitting according to asecond embodiment of the present invention,

FIG. 10 is a perspective view showing that the connection fitting ofFIG. 9 is inserted into the winding terminal receiving portion,

FIG. 11 is a schematic sectional view of a known compressor to which thepresent invention is applied,

FIG. 12 is a top plan view of a conventional motor stator,

FIG. 13 is a perspective view of the connection fitting in FIG. 12, and

FIG. 14 is an explanatory view showing a conventional lead wireattachment structure in which winding terminal receiving portions arecollectively disposed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described hereinafter indetail with reference to the drawings.

FIG. 1 shows a first embodiment of an electric motor according to thepresent invention. This embodiment relates to a stator 4 of a motor 1 aincorporated in a compressor 1 mounted on an air conditioner as shown inFIG. 11.

As shown in FIG. 1, the stator 4 is constituted of a stator core 5having a plurality of (six in a shown case) magnetic pole teeth disposedin a peripheral direction with a predetermined interval to jut outtoward a central portion (rotor), and stator windings 7 a to 7 f woundaround the respective magnetic pole teeth of the stator core 5 viainsulating members 6. In a top end surface portion of the stator core 5,a plurality of winding terminal receiving portions 8 a to 8 f aredisposed integrally with the insulating members 6. These windingterminal receiving portions 8 a to 8 f are dispersed and disposed on theend surface portion of the stator core 5 in the peripheral direction toaccept winding ends of the respective stator windings 7 a to 7 fdisposed in the vicinity.

The winding 7 a and the winding 7 d positioned opposite to the windingare continuously wound around to constitute a first phase winding,similarly the windings 7 b and 7 e are continuously wound around toconstitute a second phase winding, and further the windings 7 c and 7 fare continuously wound around to constitute a third phase winding. Awinding terminal 9 a drawn from the winding 7 a is attached as a windingstart end of the first phase winding to the winding terminal receivingportion 8 a, and a winding terminal 9 d drawn from the winding 7 d isattached as a winding finish end of the first phase winding to thewinding terminal receiving portion 8 d. Similarly, a winding terminal 9c drawn from the winding 7 c is attached as a winding start end of thesecond phase winding to the winding terminal receiving portion 8 c, anda winding terminal 9 f drawn from the winding 7 f is attached as awinding finish end of the second phase winding to the winding terminalreceiving portion 8 f. Furthermore, a winding terminal 9 e drawn fromthe winding 7 e is attached as a winding start end of the third phasewinding to the winding terminal receiving portion 8 e, and a windingterminal 9 b drawn from the winding 7 b is attached as a winding finishend of the third phase winding to the winding terminal receiving portion8 b. The stator windings 7 a and 7 d, 7 b and 7 e, and 7 c and 7 f inpositions mechanically deviating from each other by 180° arecontinuously wound around, and portions corresponding to middles areconnected in common to form a three-phase system neutral point. Afterattaching the winding terminals 9 a to 9 f to the respective windingterminal receiving portions 8 a to 8 f, a conductive first connectionfitting 10 for fixing the winding terminal (see FIGS. 2, 3) is insertedthereinto.

As shown in FIG. 2, for the first connection fitting 10, one flat metalplate is bent substantially in a U shape and processed to obtain a sizesuch that the fitting can be inserted into the winding terminalreceiving portions 8 a to 8 f, and a cutout 20 slightly narrower than adiameter of the stator windings 7 a to 7 f (hereinafter referred to asthe winding 10) is formed along a height from a bottom to a middle ofthe U-shaped metal plate. One tip end portion of the U-shaped metalplate is turned back toward the other tip end portion to form anengaging piece 10 a for engaging with a lead wire unit connectionterminal described later, and a plurality of projections 10 b forengaging with inner walls of the winding terminal receiving portions 8 ato 8 f are formed in a side surface of the plate.

As shown in FIG. 3, after inserting a winding terminal 9 (genericnumeral of 9 a to 9 f) into a winding terminal receiving portion 8(generic numeral of 8 a to 8 f) to the outside from the inside, and byinserting the first connection fitting 10 into the winding terminalreceiving portion 8 in such a manner that the cutout, that is, groove 20holds the winding terminal, the groove 20 breaks a winding insulatingcoating film, and the first connection fitting 10 is electrically andmechanically connected to the winding terminal 9. This connection systemis known as a “pressure contact type terminal”.

A terminal plate 21 disposed on the top end surface of the stator core 5will next be described. As shown in FIG. 4, the terminal plate 21 isformed in an annular shape to be held in the top end surface of thestator core 5, and is provided with a guide groove 22 for leading a leadwire around in the peripheral direction of the stator 4. A width of theguide groove 22 is set to be substantially equal to a diameter of a leadwire 23 (see FIG. 5). A depth of the guide groove 22 is set to be twiceor more as large as the diameter of the lead wire such that two or morelead wires 23 are superposed and accommodated as shown in FIG. 5. Duringleading around of the lead wire 23, the lead wire 23 is pushed into theguide groove 22 and led around along the guide groove 22. Thereby, thelead wire 23 is fixed, and an operation of leading around the lead wireis facilitated.

In the terminal plate 21, connection fitting receiving portions 25 a to25 f for containing a second conductive connection metal 24 (see FIG. 7)along the guide groove 22 are disposed on an outer peripheral side ofthe terminal plate 21 and dispersed in the peripheral direction. Whenthe terminal plate 21 is disposed in the stator, the receiving portions25 a to 25 f are disposed in positions opposite to the winding terminalreceiving portions 8 a to 8 f (see FIG. 1) formed and disposedintegrally with the insulating member 6 on the end surface of the statorcore 5.

For a first phase lead wire 23 u attached to the terminal plate 21, asshown in FIG. 6, one terminal thereof is inserted and disposed into thelead wire connection fitting receiving portion 25 a from the peripheraldirection, and subsequently a terminal plate side engagement portion 24a of the second connection fitting 24 shown in FIG. 7 is inserted fromabove and fixed. After leading the lead wire 23 u substantially aroundthe half of a periphery along the guide groove 22 (see FIG. 4, 5) fromthe connection fitting receiving portion 25 a, the lead wire 23 u ispassed through the connection fitting receiving portion 25 d positionedopposite to the connection fitting receiving portion 25 a, and theterminal plate side engagement portion 24 a of the second connectionfitting 24 is inserted into the connection fitting receiving portion 25d to fix the lead wire 23 u. After the lead wire 23 u is further drawnout of a lead wire exit 26, the other terminal portion of the wire isconnected to a power source connector 27.

Similarly, for a lead wire 23 v, one terminal thereof is disposed in theconnection fitting receiving portion 25 b, and the terminal plate sideengagement portion 24 a of the second connection fitting 24 is insertedinto the connection fitting receiving portion 25 b to engage with theterminal of the lead wire 23 v, and fixed. After leading the lead wire23 v substantially around the half of the periphery along the guidegroove 22 from the connection fitting receiving portion 25 b, the leadwire 23 v is passed through the connection fitting receiving portion 25e positioned opposite to the connection fitting receiving portion 25 b,and the terminal plate side engagement portion 24 a of the secondconnection fitting 24 is inserted into the connection fitting receivingportion 25 e. After the lead wire 23 v is drawn out of the lead wireexit 26, the other lead wire terminal is connected to the power sourceconnector 27.

Also for a lead wire 23 w, one terminal thereof is disposed in theconnection fitting receiving portion 25 f, and the terminal plate sideengagement portion 24 a of the second connection fitting 24 is insertedinto the connection fitting receiving portion 25 f to engage with theterminal of the lead wire 23 w, and fixed. Moreover, after leading thelead wire 23 w substantially around the half of the periphery along theguide groove 22 from the connection fitting receiving portion 25 f, thelead wire 23 w is passed through the connection fitting receivingportion 25 c positioned opposite to the connection fitting receivingportion 25 f, and the terminal plate side engagement portion 24 a of thesecond connection fitting 24 is inserted into the connection fittingreceiving portion 25 c. After the lead wire is drawn out of the leadwire exit 26, the other terminal of the lead wire 23 w is connected tothe power source connector 27. The lead wires 23 u, 23 v, 23 w drawn outof the lead wire exit 26 are twined into one bunch and connected to thepower source connector 27.

Additionally, the second connection fitting 24 shown in FIG. 7 isprovided with the terminal plate side engagement portion 24 a formed byfolding back one end of one metal plate in a rectangular parallelepipedshape to obtain a size such that the portion can be inserted into thelead wire receiving portion 25 a. Moreover, in order to electricallyconnect the terminal plate side engagement portion 24 a to the leadwires 23 u, 23 v, 23 w, the portion is provided with a groove portion 28whose entrance is formed in a tapered shape, and a click 28 a forpreventing the lead wire from dropping is disposed for the grooveportion 28 in the vicinity of the entrance of the groove portion 28.Furthermore, for the second connection fitting 24, the other end of themetal plate is used to form a terminal conductor 29 jutting out in afork shape, which is inserted into the first connection fitting 10inserted in the winding terminal receiving portions 8 a to 8 f toconstitute the connection fitting. The terminal conductor 29 is providedwith a groove portion 30 for passing the winding terminals 9 a to 9 ftherethrough when the conductor is inserted into the first connectionfitting 10. Additionally, the groove portions 28 and 30 are designed tobe in an orthogonal relation such that the lead wire 23 crosses at rightangles to the winding terminals 9 a to 9 f.

The terminal plate 21 assembled by the aforementioned constitution isdisposed on the end surface of the stator core 5 as shown in FIG. 8 byaligning the second connection fitting 24 with the first connectionfitting 10, and six projections 29 of the second connection fitting 24attached to the terminal plate 21 are simultaneously inserted into theengaging pieces 10 a of the first connection fittings 10, so that thewinding terminals 9 a to 9 f are connected to the lead wires 23 u, 23 v,23 w.

The second connection fitting 24 inserted in the lead wire receivingportion 25 a in this manner is connected to the first connection fitting10 inserted in the winding terminal receiving portion 8 a, the secondconnection fitting 24 inserted in the lead wire receiving portion 25 dis connected to the first connection fitting 10 inserted in the windingterminal receiving portion 8 d, the second connection fitting 24inserted in the lead wire receiving portion 25 b is connected to thefirst connection fitting 10 inserted in the winding terminal receivingportion 8 b, the second connection fitting 24 inserted in the lead wirereceiving portion 25 e is connected to the first connection fitting 10inserted in the winding terminal receiving portion 8 e, the secondconnection fitting 24 inserted in the lead wire receiving portion 25 fis connected to the first connection fitting 10 inserted in the windingterminal receiving portion 8 f, and the second connection fitting 24inserted in the lead wire receiving portion 25 c is connected to thefirst connection fitting 10 inserted in the winding terminal receivingportion 8 c. That is to say, the lead wire 23 u is connected to thewinding terminals 9 a and 9 d drawn out of the stator windings 7 a and 7d, the lead wire 23 v is connected to the winding terminals 9 b and 9 edrawn out of the windings 7 b and 7 e, and the lead wire 23 w isconnected to the winding terminals 9 c and 9 f drawn out of the windings7 c and 7 f.

Additionally, in FIG. 8, the power source connector 27, and lead wire 23formed of the lead wires 23 u, 23 v, 23 w constitute a lead wire unit31.

According to the aforementioned first embodiment, since the terminalplate 21 is disposed on the stator to complete the connection of thewinding terminal to the lead wire, an attaching process can besimplified. Moreover, since the lead wire is led around in theperipheral direction of the stator, there is no flexing of the lead wirein the connection fitting, and wiring can be led around without anytensile force. Furthermore, since the terminal plate 21 is provided withthe guide groove 22, a lead-out wire is fixedly disposed, theleading-around operation can securely and easily be performed, and thewiring can be prevented from jumping out or crossing.

A second embodiment of the motor of the present invention will next bedescribed.

In the second embodiment shown in FIG. 9, a connection fitting 100 isused in which a connection fitting 101 to be connected to the windingterminal 9 is integrally molded with a connection fitting 102 to beconnected to the lead wire 23. First, the winding terminal 9 is disposedin the winding terminal receiving portion 8, and subsequently, theconnection fitting 100 is inserted/attached into the winding terminalreceiving portion 8 as shown in FIG. 10. This fixes the winding terminal9 to the winding terminal receiving portion 8, and additionallyelectrically connects the connection fitting 102 to the winding terminal9. Moreover, the terminal plate 21 in which the lead wire 23 is ledaround along the guide groove 22 is disposed on the end surface of thestator core 5 with the connection fitting 100 attached thereto, and aplurality of connection fittings 100 are simultaneously inserted andattached into lead wire receiving portions 25 of the terminal plate 21.This realizes electric connection of the lead wire 23 to the connectionfitting 100. Thereby, the electric connection of the stator windings 7 ato 7 f to the lead wire 23 is completed.

According to the aforementioned second embodiment, an operation (sixprocesses) of inserting the lead wire side connection fittings into theterminal plate becomes unnecessary, the number of processes decreases,and the operation is further simplified as compared with the firstembodiment.

What is claimed is:
 1. An electric motor comprising: a plurality ofwindings wound around a stator core; a plurality of winding terminalreceiving portions, disposed on an end surface portion of the statorcore at an interval in a peripheral direction, for individuallyreceiving a plurality of winding terminal portions; a plurality of firstconductive connection fittings, attached to said respective windingterminal receiving portions, for fixing said winding terminal portionsto said winding terminal receiving portions and for electricallyconnecting with said winding terminal portions; a plurality of secondconductive connection fittings whose one surface side is provided with aprojection for contacting said first connection fitting and whose othersurface side is provided with a lead wire which is electricallyconnected to said winding terminal portion and which extends through thesecond conductive connection fittings in the peripheral direction ofsaid stator core; and a terminal plate having connection fittingreceiving portions to which said plurality of second connection fittingsare attached and which are dispersed in the peripheral direction so asto correspond to said plurality of winding terminal receiving portions.2. The motor according to claim 1 wherein said winding terminal portionis drawn out in a radial direction of said stator and fixed to saidfirst connection fitting.
 3. The motor according to claim 1 wherein saidfirst connection fitting is constituted as a pressure contact typeterminal in which a winding insulating coating film beforehand disposedon said winding receiving portion is broken during attachment to saidwinding receiving portion to permit the winding to conductively contactthe first connection fitting.
 4. The motor according to claim 1 whereinsaid second connection fitting is constituted as a pressure contact typeterminal in which an insulating coating film of the lead wire is brokenby attaching the lead wire to a groove to conductively contact thesecond connection fitting.
 5. The motor according to claim 1 whereinsaid terminal plate comprises a lead wire exit, and a lead wire guidegroove running in the peripheral direction to guide the lead wire fromsaid second connection fitting to the lead wire exit, and the guidegroove has a width substantially equal to a diameter of the lead wire.6. The motor according to claim 1 wherein said terminal plate has a leadwire exit, and a lead wire guide groove running in the peripheraldirection to guide the lead wire from said second connection fitting tosaid lead wire exit, and the guide groove has a depth in which aplurality of said lead wires can be bundled and accommodated.
 7. Anelectric motor comprising: a plurality of windings wound around a statorcore; a plurality of winding terminal receiving portions, disposed on anend surface portion of said stator core at an interval in a peripheraldirection, for individually receiving a plurality of winding terminalportions; a plurality of connection fittings which fixes said windingterminal portion to said winding terminal receiving portion and whichelectrically connects with said winding terminal portion on one side,said plurality of connection fittings having a groove through which alead wire connected to said winding terminal portion passes in theperipheral direction of said stator core on the other side; and aterminal plate having connection fitting receiving portions to whichsaid plurality of connection fittings are attached and which aredispersed in the peripheral direction so as to correspond to saidplurality of winding terminal receiving portions, said connectionfitting being beforehand attached to either of said winding terminalreceiving portion and said terminal plate.
 8. The motor according toclaim 7 wherein said winding terminal portion is drawn out in a radialdirection of the stator and fixed to said connection fitting.
 9. Themotor according to claim 7 wherein said first connection fitting isconstituted as a pressure contact type terminal in which a windinginsulating coating film beforehand disposed on said winding receivingportion is broken during attachment to said winding receiving portion topermit the winding to conductively contact the connection fitting. 10.The motor according to claim 7 wherein said connection fitting isconstituted as a pressure contact type terminal in which an insulatingcoating film of the lead wire is broken by attaching the lead wire to agroove to conductively contact the connection fitting.
 11. The motoraccording to claim 7 wherein said terminal plate comprises a lead wireexit, and a lead wire guide groove running in the peripheral directionto guide the lead wire from said second connection fitting to the leadwire exit, and the guide groove has a width substantially equal to adiameter of the lead wire.
 12. The motor according to claim 7 whereinsaid terminal plate has a lead wire exit, and a lead wire guide grooverunning in the peripheral direction to guide the lead wire from saidsecond connection fitting to said lead wire exit, and the guide groovehas a depth in which a plurality of said lead wires can be bundled andaccommodated.